My company hires engineers wherever they are. We're only incorporated in a few countries, the way we work is to engage a firm whose business it is to be incorporated in many countries so that they can hire people in those countries as full time employees, and contract them to our company. This firm charges a flat fee per person per year, and it's not a lot. I've been told that we'd have to have at least 5 people in a single country before incorporating in that country would cost the same as using this firm. They handle all the local obligations, payroll, entitlements, tax, superannuation, etc. I don't know how it works, but we even are able to get stock options, and I've never heard of any problems with that from any of my coworkers in any other countries. Other things like leave - our local job contracts conform to local law for leave allowances, and then we just work it out with our managers - we have an HR system that seems to be able to easily handle different leave policies for each employee, and if there's any problems, you just tell your manager and it gets sorted, no big deal.